EAPSI: Discovering Novel Functions of Protein Repeats Critical to Gene Expression

Babokhov Michael, Medford MA

Investigators

Abstract

Understanding how the genome is read by the cellular machinery to allow the cell to survive is a major focus of biological research. One specific enzyme of the cellular machinery contains an unusual region of highly repetitive structure critical to gene expression. However the reason for having so many repetitions of the same structure or the specific function of individual repeats is currently unknown. This project will develop novel genetic tools to investigate the role of these repeats in controlling gene expression. The development and application of this approach will be performed in collaboration with Dr. Hiroaki Kato of the Shimane University School of Medicine in Japan, an expert in the control of gene expression by the cellular machinery. Results obtained from this work will drive further understanding of the role of protein repeats during gene expression in both healthy and sick cells. Progress through the transcription cycle is tightly regulated by the heptad repeats of the C-terminal domain of RNA polymerase II. These repeats, numbering 26 in yeast and 52 in humans, are post-translationally modified to recruit additional protein complexes to the site of transcription. This project will investigate specific stretches of repeats to understand if identical protein repeats can have unique functions in recruiting protein factors. Collaboration with Dr. Kato will provide access to the fission yeast model organism to complement previous studies in budding yeast. A new system for studying RNA polymerase II based upon a method used in budding yeast will be developed in fission yeast. The system will then be applied to study repeat-specific protein recruitment during heterochromatin silencing ? a pathway present in fission yeast (and shared with higher eukaryotes) but absent in budding yeast. This comparative approach will uncover additional spatial mechanisms of the C-terminal domain repeats in regulating the activity of RNA polymerase II. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science (JSPS).